Coating applicator for flexible strip material



Dec. 4, 1956 D. G. WILLIAMSON ET 2,772,655

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United States Patent COATING APPLICATOR FOR FLEXIBLE STRIP MATERIAL Donald Williamson and Melvin W. Snover, Winnetka, and Hrlmar A. Andresen and Raymond H. Andreseu, Chicago, Ill., assignors to Williamson Adhesives, Inc., Skokie, 11]., a corporation of Illinois Application May 14, 1953, Serial No. 355,094

Claims. (Cl. 118126) This invention relates to an applicator for and method of applying liquid to flexible strip material. The applia cator of our invention can be used for applying coatings of various types, including decorative, protective and adhesive coatings, or the liquid to be applied may be an activating liquid for remoistening or solvent activating an already coated flexible strip.

The applicator of our invention includes means defining a reservoir for the liquid to be applied, a stationary member, :or roll, having an arcuate surface extending into the reservoir, and a resiliently biased doctor blade having a blunt, or rounded edge constantly urged toward the surface of the stationary roll on the side thereof that the flexible strip emerges from the reservoir. Guiding means are provided for directing the flexible strip into contact with the stationary roll, and the strip is initially threaded around the under side of the roll and between the roll and the doctor blade, after which the sub-assembly supporting the roll and doctor blade are moved into place with the roll partially immersed in the reservoir of liquid. The spring urged doctor blade serves the purpose of spreading and gauging the coating or film applied to the flexible strip as it is drawn past the doctor blade.

One of the various uses of our applicator is in connection with the application to strips of flexible material, such as paper, cloth, and the like, of a pressure-sensitive adhesive composition. Our device has proved to be very satisfactory for the making, right on the job, of pressuresensitive tape, so that it can be made as it is needed and used on the spot, without the necessity of winding the tape into rolls, spooling or packaging the same. The cost saving is considerable.

It is therefore an important object of our invention to provide an applicator of novel and improved construction for the application of liquids, either as coatings, films, or activating solvents, to flexible strip material.

It is a further important object of thisinvention to provide an applicator through which flexible strip material can be manually drawn and the strip automatically treated on one side with the liquid while the other side of the strip remains untreated.

It is a further important object of this invention to provide an applicator for use on-the-job and by means of which flexible strip material drawn therethrough is conveniently and satisfactorily treated to the desired extent without requiring more than the simplest type of adjustments, if any.

It is a further important object of this invention to provide a method of treating flexible strip material with a liquid while being held under tension in contact with a stationary arcuate surface submerged within a body of the treating liquid and controlling the amount and distribution of the applied treating liquid as the strip emerges from the reservoir of liquid and while still in contact with the arcuate stationary surface.

Other and further important objects of this invention will become apparent from the following description and appended claims.

On the drawings:

Figure 1 is a longitudinal vertical sectional view of the applicator of our invention.

Figure 2 is a top plan view of the applicator.

Figure 3 is an end elevational view of the applicator, with parts broken away.

Figure 4 is a fragmentary enlarged view of the other end of the applicator from that shown in Figure 3.

As shown on the drawings:

The applicator of our invention, which is generally indicated by the reference numeral 10, may suitably be in the form of a rectangular housing or casing having end walls 11 and 12 and connecting side walls 13. The bottom of the casing is closed by means of a relatively thin sheet 14, which may suitably be of metal, and which extends between the end walls 11 and 12 and is secured, as at 15, to a shoulder formed in the lower part of the end wall 11. The bottom wall sheet 14 is bent upwardly, as at 16, in the direction of the end wall 12 and is provided with a curved end portion 17 which is in contact with the inner surface of the end wall 12 and projects inwardly and away from said surface at its extremity 17a. The purpose of the curvature of the bottom wall 14 will be more fully apparent as the description proceeds.

The other end wall 11 is provided, near the bottom thereof, with a transverse slot 18, which is relatively thin and which extends only part way toward the side walls 13. The slot 18 serves to admit a strip 19 (Fig. l) of the flexible material to be treated within the applicator. A pair of gate members 20 and 21 cooperate to control the effective width of the slot 18. For that purpose, each of the gate members 20 and 21 is adjustably mounted for movement laterally toward and away from the side walls 13 of the applicator. This is made possible by the provision of slots 22 and 23, through which extend posts 24 and 25, the upper ends of which are threaded for receiving butterfly nuts 26 and 27. The inner ends of the gates 20 and 21 are provided, respectively, with flanges 28 and 29 which are formed with opposed, parallel plane surfaces for adjustment against the edges of the strip 19 (Fig. 2).

An inner bottom wall and guiding surface, generally indicated by the reference numeral 30, is mounted above and in generally equi-spaced relation to the bottom wall 14 throughout the latters extent. Said inner bottom wall 30 is secured, as at 31 (Fig. l) to the upper edge of the slot 18 and is provided with upstanding flanges 32 along its lateral edges for securing to the side walls 13. Since the applicator is suitably made throughout of metal, parts may be easily welded, or brazed, together, wherever desired or necessary. It will be noted that the flanges 32 (of which only one appears in the drawing) provide a liquid tight joint with the side walls 13 up to a point indicated by the reference numeral 33 (Fig. l), which, as will later appear, is above the level of the reservoir of liquid indicated by the dash line L. Thus, the wall 30 provides a bottom wall for the reservoir of treating liquid.

Said bottom wall 30 also serves as a guide for the strip 19, introduced into the applicator through the slot 18 into the space S between the two walls 14 and 30. The wall 30 is provided at its inner end with a curved portion 34, which is generally curved about the same axis as the curved portion 17 of the wall 14, but the curved portion 34 continues upwardly and inwardly beyond the other wall end 17a to terminate at 34a.

The end wall 11 is somewhat higher than the end wall 12 and in conjunction with a transverse integral, intermediate wall portion 35 (Fig. 1) provides a plane upper surface 36 to which is attached a closure member, or cap 37, as by means of screws 38. The cap 37 is provided centrally thereof with a generally cylindrical boss 83, through which extends a bore 39 for receiving a cylindrical tube 40 that serves as a conduit from an auxiliary reservoir (not shown) for supplying the treating liquid to the applicator. A coupling 89 may be used to connect the tube 40 with such auxiliary reservoir, and the latter may be merely an inverted bottle of the treating liquid, from which the liquid will flow as required to keep the level L substantially constant. The boss 88 has an inner annular channel 41, in which is mounted a gasket 52 that serves as a seal for the feeding tube 49 while permitting relative sliding vertical movement of the tube within the bore 39. The lower end 43 of said filling tube ,8 determines the level L of the reservoir of liquid, indicated generally by the letter R, within the applicator.

The upper end of the applicator toward the end wall 12 has an opening between said end wall and the transverse barrier wall 35 that is normally closed by a cover 43 that forms a part of a sub-assembly (Fig. 1). To facilitate the mounting of the sub-assembly 44 and its removal, the transverse wall 35 is provided with one or more aligning posts 45 for reception into corresponding recesses 46 in the adjacent end of the cover member 43, while the cover member itself is provided with a recess 4-8 for the reception of an aligning post 49 projecting above the upper end of the end wall 12. The cover 43 extends slightly beyond said end wall 12 and a U-shaped bail 59 is suspended therefrom for interengagement with an embossment 51 on said end wall 12. When the. bight of the bail St) is inserted under the lower edge of said embossment 5i. and in engagement therewith, the subassembly $4 is held properly in position, whereas if it is desired to remove the sub-assembly, it is necessary merely to swing the bight of the bail 50 out from engagement and lift up the sub-assembly from the end nearest the end wall 12, while at the same time pulling the sub assembly away from the transverse wall 35.

Said sub-assembly 44- includes dependent plates 52 suitably secured to the cover 43 somewhat inwardly of the side edges thereof so as to lie within the side walls 13 or" the housing when the sub-assembly is in place. A stationary roll 53 is mounted between the pair of dependent plates 52, as by means of fastening devices 54 indicated in dotted lines in Figure l. The roll 53, which is cylindrical in outer contour, is of rigid material, such as metal, and is so arranged and of such dimensions that it extends from just adjacent the cover 43 into the reservoir R and into close proximity with the downturned end 4a of the inner bottom wall and guide member 30. The cover 53 is slotted at 55 (Fig. 2) to provide an exit for the emergence of the strip 19. Adjustable guiding and gauging members 56 and 57, in general similar to the iembcrs and 21, provide an exit gate of the width of the strip 7.5 through which the strip emerges from the interior of the applicator. The adjustable members 56 and 57 are adjusted into alignment with the flanges 28 and 29 of the other adjustable gate members and 21 so as to keep the strip 19 in relatively fixed position as it passes through the applicator. As will be evident, the applicator could be built with a plurality of adjustable gating and guiding members for accommodating a plurality of separate strips all at the same time, since, as will later be pointed out, there is nothing to prevent several strips being drawn through the applicator at the same time, either at the. same or at ditlerent speeds.

The sub-assembly 44 also includes a pivotally mounted doctor blade 60, which is pivoted about a pin 61 and which is blunt, or rounded, at its lower end 62 for cooperation with the stationary roll 53, as the web 19 is drawn there-between A ribbon of resilient metal constituting a spring 63 biases the lower end of the doctor blade in the direction of the stationary roll 53. For this purpose, the spring 63 is secured at its upper end by means of a rivet 64 to the under surface of the cover 43 and is curved at its free end 65 to provide a convex portion for contact with said doctor blade 60. A threaded member 66, extending through an internally threaded opening 67 in the cover 43, has a lower tapered end 63 that function as a limit or stop for the upper end of the doctor blade 62. The upper end of said threaded member 66 is provided with a knurled end 69 for adjustment thereof and with a knurled nut 70 for securing the threaded member in its adjusted position. Thus, while the spring 63 constantly urges the lower end of the doctor blade 66 toward the stationary roll 53, and toward the strip 19 as it passes thereover, the threaded adjusting member 6% acts as a stop for the upper end of the doctor 60 to limit the spacing between the lower doctor blade edge 62 and the surface of the stationary roll 53. The doctor blade 69 thus serves to gauge the thickness of the coating applied to the strip 19.

The upper portion of the stationary roll 53 projects slightly into the slot 35 and the adjacent end of the cover 43 is beveled at its lower edge, as at 71, to provide clearance therebetween. The upper portion of the same edge of the cover 43 is provided with an upwardly sloping surface 72 over which the strip 19 passes in its movement out through the slot 35 onto the upper surface 73 of the cover 43. The free end 19a, which normally projects beyond the upper edge of the end wall 12, is where the pulling tension is applied, usually manually, to draw the strip 19 through the applicator.

In using the applicator for the first time, the operator removes the sub assembly 44 before any liquid is introduced into the housing to form the reservoir R. The strip 19 can easily be threaded through the guiding space S whether the reservoir has been filled, or not, since if the strip is fed in through the slot 18 the free end thereof will naturally follow the smooth contours of the walls 14 and 30 until the free end can be grasped up above the extreme edge 17a. The free end of the strip 19 is then led around the stationary roll 53, past the blunt end 62 of the doctor blade and out through the slot 35.

When the sub-assembly is lowered into position, there is little, if any, tendency of. the liquid to pass in back of the strip, between the strip and the surface of the stationary roll, since the strip floats up into contact with the surface of the stationary roll 53. If the strip is wet with the adhesive on the wrong side, this soon clears up as the strip is drawn through the applicator. in fact, regardless of the viscosity of the treating liquid in the reservoir R, no difficulty has been experienced, once the applicator is in use, with the liquid tending to get between the strip and the stationary roll and thus come into contact with the other side of the strip from that which is intended to be coated, or treated.

After the sub assembly has been secured in place by engaging the bail under the embossment 51, the applicator is ready for use. The doctor blade 6% will have been adjusted by means of the threaded member 66 to apply the correct amount of pressure against the surface of the strip 19 as it passes around the stationary roll 53, this depending upon the type of operation being carried out. An auxiliary supply of the treating liquid may also have been connected to the tube 4%) so that as the applicator is used, the liquid from the tube will run into the reservoir R and maintain the level L substantially constant. it will, of course, be understood that as the tape is treated and made ready for use, lengths of it may be torn or severed from the balance or" the strip, and such lengths either used immediately or temporarily set aside for subsequent use. One of the advantages of our applicator is that it is adapted for the treating and dispensing of a flexible strip at any point where the finished strip is to be used, so that there usually is no need to provide means for handling and storing the strip material for any length of time before it is used.

As a result of considerable experimentation we found that many of our problems were solved through the use of a doctor blade having a blunt, or rounded, working edge, as exemplified by the rounded edge 62. As the strip 19 drawn over the surface of the stationary roll 53 and in between the rounded end 62 and said roll surface, said rounded end 62, depending upon the amount of the biasing action of the spring 63, bears with more or less pressure against the coated or treated surface of the web. If the treating liquid is relatively viscous, so that there would be a tendency for a surplus :of the liquid to adhere to the exposed surface of the strip 19, then the rounded edge 62 Will remove any excess of liquid and also spread, or distribute, whatever liquid continues to adhere to the exposed surface in passing into the nip between said rounded edge and the stationary roll. The rounded edge 62 of the doctor blade thus serves as a wiper, as well, as a doctor for removing excess of liquid. The edge 62 should be positioned just above the level L of the liquid in the reservoir so that any excess of liquid can fall back into the reservoir R, and also so that there is no substantial drying out of the adhesive between its point of application and its point of contact with said edge 62.

The applicator is capable of operating, with liquids of various types and characteristics. A few examples of the various categories into which the liquids, or at least the flowable treating materials may fall, are: coatings of a decorative, protective or adhesive character; and surface activating or deactivating applications, which may include the remoistening or solvent activating of films or coatings already present on the flexible strip, or for deactivating other types of surfaces. An ordinary gummed strip may, for instance, be drawn through our applicator for moistening with water, which would then be the liquid within the reservoir R.

Since our applicator may find its greatest use in connection with the application of adhesive coatings to flexible strip material, we shall briefly mention some of the various types of liquid adhesives. These would include water soluble adhesives of the dextrin, starchy, casein, animal glue or soluble gum or resin type; colloidal slutions of animal glue, starch, or the like; colloidal dispersions and emulsions, with either water or an organic solvent as the continuous liquid phase; resin solutions; hot melts of thermoplastic resins, waxes and elastomers, or mixtures thereof; and heat activating compositions, which may be combinations of resins having latent adhesive properties that are developed by the application of heat.

Some common adhesive compositions of the water soluble type are represented by the following:

Example 5 Percent by weight Rubber 15.0 Plasticizer 15.0 Naphtha 70.0

Among the self-supporting flexible materials that may be used in strip ribbon, tape or other more or less continuous web form may be mentioned paper, cloth, plastic, metal, and wood veneer. The metal, of course, would be in the form of thin sheets, foil, or the like, and would include steel aluminum and lead.

One of the advantages of our applicator and dispenser already alluded to is that of being adapted for use with intermittently run equipment, as for instance box making equipment, where the flexible strip material maybe treated, coated or the like only as and when needed. It is not necessary, therefore, to use expensive, ready-made tape that must be moistened before being applied, or ready-made pressure sensitive tape. The latter is relatively more expensive because of all of the added steps of spooling and packaging, and in some instances supplying special release surfaces to facilitate unwinding without de-lamination.

It will be understood that modifications and variations may be eflected without departing from the scope of the novel concepts of the present invention.

We claim as our invention:

1. An applicator for applying a liquid to a flexible backing strip, which comprises an open-top casing having bottom, side and end walls, a separate wall member spaced from said bottom and one end wall and joined to said side and other end Walls to form a reservoir there- .above for said liquid and a guiding surface under said reservoir, said other end wall'having a slot for admitting said flexible strip for passage along said guiding surface, a stationary member having an arcuate surface extending into said reservoir, a doctor blade resiliently urged toward said arcuate surface, and a closure for said open top providing a slot above said stationary member for the Withdrawal therethrough of said strip after passage thereof through said reservoir in contact with said stationary member and past said doctor blade.

2. An applicator for applying a liquid to a flexible backing strip, which comprises an open-top casing having bottom, side and end walls, a separate wall member spaced from said bottom and one end wall and joined to said side and other end walls to form a reservoir thereabove for said liquid and a guiding surface under said reservoir, said other end wall having a slot for admitting said flexible strip for passage along said guiding surface, a stationary member having an arcuate surface extending into said reservoir, a doctor blade resiliently urged toward said arcuate surface, a closure for said open top providing a slot above said stationary member for the withdrawal therethrough of said strip after passage thereof through said reservoir in contact with said stationary member and past said doctor blade, means supporting said stationary member and said doctor blade as a part of said closure, and means removably securing said closure in place upon said one end wall.

3. An applicator for applying a liquid to a flexible backing strip, which comprises an open-top casing having bottom, side and end walls, a separate wall member spaced from said bottom and one end wall and joined to said side and other end walls to form a reservoir thereabove for said liquid and a guiding surface under said reservoir, said other end wall having a slot for admitting said flexible strip for passage along said guiding surface, a stationary member having a cylindrical surface extending into said reservoir, a rounded edge doctor blade resiliently urged toward said arcuate surface, and a closure for said open top providing a slot above said stationary member for the withdrawal therethrough of said strip after passage thereof through said reservoir in contact with said stationary member and past said doctor blade in contact with the rounded edge thereof.

4. An applicator for applying a liquid to a flexible strip and for thereafter dispensing said strip, which comprises a casing providing a reservoir for said liquid and an opening thereabove, a partial closure for said opening providing a dispensing slot for said strip, a stationary roll carried by said closure for submersion in said reservoir, a doctor blade also carried by said closure and normally urged toward said roll for evenly spreading said liquid as a layer on said strip and for gauging the thickness of said layer retained on said strip, and means providing a guide for said strip to direct the same toward said roll into lapping contact therewith and movement therearound past said blade and in contact therewith prior to being dispensed through said slot.

5. An applicator for applying a liquid to a flexible strip and for thereafter dispensing said strip, which comprises a casing providing a reservoir for said liquid and an opening thereabove, a partial closure for said opening providing a dispensing slot for said strip, a stationary roll carried by said closure for submersion in said reservoir, a doctor blade also carried by said closure and normally urged toward said roll for evenly spreading said liquid as a layer on said strip and for gauging the thickness of said layer retained on said strip, means providing a guide for said strip to direct the same toward said roll into lapping contact therewith and movement therearound past said blade and in contact therewith prior to being dispensed through said slot, and means releasably supporting said closure in said opening and providing for the removal of said closure, roll and doctor blade during the threading of said strip along said guide and through said dispensing slot.

6. An applicator for applying a liquid to a flexible strip and for thereafter dispensing said strip, which comprises a casing providing a reservoir for said liquid and an opening thereabove, a partial closure for said opening providing a dispensing slot for said strip, a stationary roll carried by said closure for submersion in said reservoir, a doctor blade also carried by said closure and normally urged toward said roll for evenly spreading said liquid as a layer on said strip and for gauging the thickness of said layer retained on said strip, and means providing a lower wall for said reservoir and a guide for said strip to direct the same underneath said reservoir and toward said roll into lapping contact therewith and movement therearound past said blade and in contact therewith prior to being dispensed through said slot.

7. An applicator for applying a liquid to a flexible strip and for thereafter dispensing said strip, which comprises a casing providing a reservoir for said liquid and an opening thereabove, a partial closure for said opening providing a dispensing slot for said strip, a stationary roll carried by said closure for submersion in said reservoir, a doctor blade also carried by said closure and normally urged toward said roll for evenly spreading said liquid as a layer on said strip and for gauging the thickness of said layer retained on said strip, means providing a lower wall for said reservoir and a guide for said strip to direct the same underneath said reservoir and toward said roll into lapping contact therewith and movement therearound past said blade in contact therewith prior to being dispensed through said slot, and means releasably supporting said closure in said opening and providing for the removal of said closure, roll and doctor blade during the threading of said strip along said guide and through said dispensing slot.

8. in an applicator for coating one side only of a flexible strip material wherein said material is drawn through a reservoir of a coating liquid, the improvements comprising a sub-assembly movable into and out of said reservoir as a unit and including a member having a stationary arcuate surface normally immersed in said reservoir and providing an immersed surface portion into contact with which said strip material is drawn under tension, and a doctor blade constantly urged toward an upwardly moving non-immersed portion of said strip material backed by member to hold said strip material snugly against said arcuate surface and thereby limit the application of the li uid to the surface of said strip material obverse from that in contact with said arcuate surface, said doctor blade functioning to spread said liquid as a uniform layer on said strip material and gauge the thickness of said layer retained on said strip.

9. An applicator for applying a liquid to one side only of a flexible strip and for thereafter dispensing the coated strip, which comprises a casing providing a reservoir for said liquid and an opening thereabove, a partial closure for said opening providing a dispensing slot for said strip, a member carried by said closure and operatively extending below the level of said liquid in said reservoir to provide :1 submerged stationary arcuate surface against which said strip is held under tension as said strip is drawn therepast during the act of dispensing the same through said slot, a doctor blade also carried by said closure and normally resiliently biased toward said arcuate surface a; a level above said normal liquid level, and means releasably supporting said closure in said opening and providing for the removal of said closure from said opening, said doctor blade having an arcuate edge functioning to spread said liquid as a uniform coating on said strip material and to gauge the thickness of said coating retained on said strip.

10. In a device for applying a liquid to a flexible strip, a casing forming a reservoir for said liquid, a sub-assembly for cooperation with said casing and relatively removable with respect thereto, said sub-assembly comprising supporting members, an arcuate member dependent therefrom in stationarily fixed relation thereto for partial submergence into the liquid in said reservoir, a doctor carried by said supporting members and having a convex portion in opposed closely spaced relation to a portion of said arcuate member above said liquid, and means also carried by said sub-assembly for adjustably maintaining the spacing between the relative portions of said arcuate and said convex portions to spread said liquid and gauge the quantity of a coating thereof applied to a strip drawn against and over said arcuate member through said reservoir and past said doctor out of said reservoir.

References Cited in the file of this patent UNITED STATES PATENTS 1,171,097 Cummings Feb. 8, 1916 1,202,664 Brownson Oct. 24, 1916 1,334,190 Swartout Mar. 16, 1920 1,428,021 Faucette Sept. 5, 1922 1,539,518 Schreiber May 26, 1925 1,667,408 Allen Apr. 24, 1928 1,914,375 Krueger June 20, 1933 1,993,055 Gertsenberg Mar. 5, 1935 2,220,071 Avery Nov. 5, 1940 2,257,373 Fanselow Sept. 30, 1941 2,341,392 Shreckhise Feb. 8, 1944 2,368,176 Trist Jan. 30, 1945 2,470,093 Crowder et al May 17, 1949 2,631,562 Gerard Mar. 17, 1953 

